History of Navigation

This is an example of the sailing directions included in The English Pilot, Fourth Book. They describe sailing along the Maine coast, though the top of the page says Newfoundland. See online at Boston Public Library electronic access.

This box of instruments was owned and used by Captain Andrew M. Ross of Searsport aboard the ship Henrietta. The dividers were used for many position plotting and calculating purposes, including measuring distances traveled, plotting offsets in celestial sight reductions, and assisting in calculations with the gunter scale.

William Bourne's A Regiment for the Sea published in 1601, includes this drawing of an astrolabe. In use, the astrolabe is hung by the top ring by one person, another sights the sun, and a third reads the scale.

The American Coast Pilot was published privately until the 1870s, when the U.S. government first published its sailing directions. This coast pilot was published by the author, Edmund M. Blunt. He also published The New American Practical Navigator for many years.

This drawing shows the use of the backstaff. It shows how the observer looks away from the sun and lines up the shadow of a vane, while sighting the horizon to find the altitude of the sun. Invented by John Davis, this drawing is from John Davis's Seaman's Secrets, published in 1595. See online access address (Book 2)

On this 1844 voyage from Liverpool, the ship Brunswick is recording its distance traveled every two hours. Captain B.H. Melcher has found the ship's longitude by taking lunar distances to two stars, and he had found his latitude by the sun.